Homework Help:
Rotating bodies, Car around a corner

1. The problem statement, all variables and given/known data
A car turns a corner with a radius of curvature of 11.1 m while braking to reduce its speed. If the brakes generate an angular deceleration of 0.5 rad/s2 what is the magnitude of the acceleration of the car half way through the corner when the car's linear speed is 9.6 m/s?

3. The attempt at a solution
What I did was I converted the linear speed into angular speed by using the first formula, then I found the time, and halved it, but the answer I'm getting for acceleration HALF WAY is not correct, I have no clue what I did wrong.
Please help1. The problem statement, all variables and given/known data
A square sheet with a uniform density and total mass m is pivoted about an axis A in one corner of the sheet and perpendicular to the plane of the sheet as shown below. If the moment of inertia of the sheet about this axis is \frac{8}{3}ma^2, what is the sheet's moment of inertia about a parallel axis, B, at the mid-point of one of its sides?

http://moodle.phys.ualberta.ca/file.php/2/questions/images/rotation/rotation-parallelaxis.png [Broken]1. The problem statement, all variables and given/known data

Staff: Mentor

You found the tangential component of the acceleration. So far, so good!

Then I used the formula
v=v0 + at
v= at
v= 5.55 m/s^2 x t
t= 9.6 m/s^2 / 5.55 m/s^2
t= 1.73
t/2 because it asks for the deceleration half way through the curve
Then I used the v=at again with half the time = 0.865 ..
then v=at
a=v/t --> 9.6 m/s / 0.865 seconds
= 11.098 m/s^2

Not sure what you're doing here. You need the radial component of the acceleration. Note that they tell you the speed, so no need for any kinematics. (Hint: The motion is circular.)

Staff: Mentor

A square sheet with a uniform density and total mass m is pivoted about an axis A in one corner of the sheet and perpendicular to the plane of the sheet as shown below. If the moment of inertia of the sheet about this axis is \frac{8}{3}ma^2, what is the sheet's moment of inertia about a parallel axis, B, at the mid-point of one of its sides?